Orthodontics is a dental specialty that treats malocclusion through the movement of teeth as well as control and modification of facial growth. This process is usually accomplished by using a continuous mechanical force to induce bone remodeling, thereby enabling the teeth to move to a better position. In this approach, orthodontic appliances provide a continuous static force to the teeth via an archwire connected to brackets affixed to each tooth or via a removable appliance such as an aligner, or some similar accessory, that fits over the dentition. As the teeth slowly move due to the force, the force is dissipated. The archwires are adjusted to add additional force and to continue the desired tooth movement. Although effective, this widely accepted approach takes about twenty four months on average to achieve success.
Dental researchers have long postulated that a pulsating force might also be used to move teeth more rapidly and to ease the discomfort of traditional orthodontics.
Mao was probably the first to prove that the use of cyclic forces could improve dental straightening in rabbits (see U.S. Pat. Nos. 6,684,639, 6,832,912, 7,029,276). Certain dynamic loading patterns (cycling force with rest periods) were shown to greatly increase bone formation compared to basic dynamic loading. Inserting rest periods is now known to be especially efficacious as it allows mechanosensitivity to be restored to the bone tissue. A point of diminishing returns is reached within each loading session. Therefore, intermittently loading cyclic force can increase the rate of bone formation significantly.
U.S. Pat. Nos. 4,244,688, 4,348,177, and 4,382,780 describe devices used to vibrate the teeth during orthodontic treatment, although each uses a different means of applying a vibration. The U.S. Pat. No. 4,244,688 patent employs a cumbersome external power source to power one to four small motors, whereas U.S. Pat. No. 4,348,177 uses pulsating fluids moved with the chewing motion of the jaw, and U.S. Pat. No. 4,382,780 uses a radio and speaker to set up a vibration. These devices are mounted on a bulky headgear that surrounds the head and are connected directly to the teeth by its intraoral portions. The devices are cumbersome, difficult to construct, expensive and are very difficult to use, thus reducing patient compliance.
U.S. Pat. No. 5,030,098 by Branford describes a hand-held device that simulates chewing in order to treat periodontal disease by increasing blood flow to the gums. The mouthpiece has a perforated malleable plate such that biting of the mouthpiece results in the plate adapting to the user's bite which, of course, varies with each user. The external vibrator imparts motion to the mouthpiece and thus the user's teeth. The device, however, uses an external power source and vibrator. Further, the dental plate is brass, and is very unpleasant to bite on, thus necessitating a second exterior coating and further complicating manufacture and cost.
U.S. Pat. No. 5,967,784 by Powers describes a similar device to that described by Branford. It too is a hand-held tooth vibrator that is simple and has an exterior motor housing connected to a vibrating interdental mouthpiece portion for gripping between the teeth of the patient. The exterior housing contains a battery and a switch for selectively operating a motor with an off-center weight attached to the motor rotating shaft for creating a high frequency vibration that vibrates the entire device. The mouthpiece is disposable, making the system affordable and more convenient to use. The patent teaches using the device to alleviate pain by inserting the interdental mouthpiece between the teeth and clenching and releasing the teeth over the mouthpiece, in an attempt to engage as many teeth as possible in the transmitted vibrations. The vibration is believed to alleviate discomfort by increasing blood flow.
The devices of Branford and Powers seem superficially similar to those of the invention herein. However, there is no recognition in either patent that the vibratory device can be used for alveolar bone remodeling or more rapid tooth movement. Furthermore, the shape of the dental plate in each case is a very flat U- or Y-shaped member that is largely ineffective for remodeling dentoalveolar bone. Additionally, the vibration is not optimized in frequency and amplitude for remodeling. Finally, neither device is entirely intraoral, and the extraoral component may cause drooling and inhibit patient compliance. The extraoral component may also lead to inhibition about use of the device in certain settings. All of these shortcomings reduce the effectiveness of these devices for craniofacial remodeling uses.
U.S. Pat. No. 6,632,088 describes a bracket with powered actuator mounted thereto to provide vibration, but this device is cumbersome, and thus may affect patient comfort and ultimately patient acceptance of the device. Further, the device locks to the bracket and archwire, and vibration of the tooth through the bracket is less than optimal, causing wear to the tooth enamel and causing discomfort.
WO2007116654 describes another intraoral vibrating mouthpiece, but the mouthpiece is complex, designed to fit over the teeth and will be expensive to manufacture. Further, to the extent that this device vibrates the brackets, it suffers from the same disadvantages above.